1. Field of the Invention
The present invention relates generally to wrenches, and, more particularly, to wrenches that are driven by a power source.
2. Description of the Prior Art
Wrenches are available in a wide variety shapes and configurations for a wide variety of applications. More specifically, wrenches have either closed ends or open ends. In certain instances, a nut or bolt head is accessible to a wrench from directly above or from directly below the nut or bolt head. That is, the wrench can cross the longitudinal axis which passes through the bolt to which the nut or bolt head is attached in order to place the wrench on the nut or bolt head. When such is the case, then either an open end or a closed end wrench can be employed for turning the nut or bolt head.
However, there are also situations in which it is desired to place the wrench on the nut or bolt head, but the nut or bolt head cannot be accessed by having the wrench cross the longitudinal axis which passes through the bolt to which the nut or bolt head is attached. For example, a nut may be positioned half way between two ends of a long rod or cable. In such a case, the nut cannot be accessed by a wrench from directly above or directly below the nut. The long portions of the rod or cable prevent such access. In this respect, it would be desirable if a wrench device were provided which permits a nut to be accessed by the wrench when the nut is positioned at an intermediate position between two ends of a rod or cable.
Wrenches are also characterized as to whether they are powered manually or powered by a nonmanual source of power. Manual wrenches come in a number of forms that are capable of accessing nuts or bolt heads in a wide variety of ways. For example, some manual wrenches can access nuts or bolt heads from directly above or directly below the nut or bolt head. Other manual wrenches can access a nut or bolt head from the side of the nut or bolt head.
Power wrenches, however, generally access a nut or bolt head from directly above or directly below the nut or bolt head. These power wrenches have a power source that rotates along the same longitudinal axis around which the nut or bolt head turns. Power wrenches are not provided that can access a nut or bolt head from the side of the nut or bolt head. In this respect, it would be desirable if a power wrench device were provided which can access a nut or bolt head from the side of the nut or bolt head.
Wrenches that permit access to a nut or bolt head from the side of the nut or bolt head are open-ended wrenches and generally include a C-shaped head. However, wrenches that have a C-shaped head are manually powered, not powered by an nonmanual power source. In this respect, it would be desirable if a power wrench device were provided which included a C-shaped head.
Moreover, wrenches that permit access to a nut or bolt head from a side generally have a lever arm and apply a torque to the nut or bolt head from a force applied tangential to the lever arm. Wrenches that have a lever arm to provide a torque to the nut or bolt head may have either a C-shaped head or a box-shaped, closed head, and such wrenches are manually powered. Generally, wrenches that permit access to a nut or bolt head from a side of the nut or bolt head, whether they have a C-shaped open head or a box-shaped closed head, are manually powered. In this respect, it would be desirable if a power wrench device were provided that permits access to a nut or bolt head from a side of the nut or bolt head whether the wrench has a C-shaped open head or a box-shaped closed head.
When manually powered wrenches are used, the mode of operation generally requires a reciprocating cranking motion. That is, the wrench head is placed on the nut or bolt head with the lever arm being in an initial position. The lever arm is moved in one direction to a certain extent to tighten or loosen the nut or bolt head as the case may be. The wrench head is removed from the nut or bolt head. The lever arm is moved back to the starting position. The wrench head is placed again on the nut or bolt head, and the steps are repeated over and over again. In contrast, when power wrenches are used, a continuous circular motion is generally present. In this respect, it would be desirable if a power wrench device were provided that permits access to a nut or bolt head from a side of the nut or bolt head and that provides a continuous circular drive motion.
As mentioned above, wrenches that permit access to a nut or bolt head from a side generally have a lever arm. Aside from its characteristic of permitting application of a tangential torque, the lever arm may serve a more basic function of extending the reach of a person's hand to tight quarters not reachable by a person's hand. In this respect, it would be desirable if a power wrench device were provided which included a lever arm that extends the reach of a person's hand to tight quarters not reachable by the person's hand.
Throughout the years, a number of innovations have been developed relating to wrenches, and the following U.S. Pat. Nos. are representative of some of those innovations: 3,097,551; 3,519,046; 4,186,629; 4,399,721; and 4,914,987. More specifically, U.S. Pat. Nos. 3,097,551, 3,519,046, and 4,186,629 disclose power wrenches which have a power source that rotates along the same longitudinal axis around which the nut or bolt head turns.
Turning to another aspect of prior art wrenches, U.S. Pat. No. 4,399,721 discloses a manually operated device in which a worm screw is used for tightening or loosening turnbuckles. In addition, U.S. Pat. No. 4,914,987 discloses a manually operated tube coupling device that uses a worm screw for tightening or loosening tube couplings. A worm screw has an advantage in being capable of being continuously turned in one direction without the need for a reciprocating start and stop action described above for wrenches employing a lever arm. In this respect, it would be desirable if a power wrench device were provided with a lever arm for easy access to certain nuts or bolt heads and which employed a worm screw that is continuously turned in one direction during operation.
Thus, while the foregoing body of prior art indicates it to be well known to use power wrenches, the prior art described above does not teach or suggest a power-driven wrench apparatus which has the following combination of desirable features: (1) permits a nut to be accessed by the wrench when the nut is positioned at an intermediate position between two ends of a rod or cable; (2) can access a nut or bolt head from the side of the nut or bolt head; (3) can include a C-shaped head; (4) permits access to a nut or bolt head from a side of the nut or bolt head whether the wrench has a C-shaped open head or a box-shaped closed head; (5) provides a continuous circular drive motion; (6) includes a lever arm that extends the reach of a person's hand to tight quarters not reachable by the person's hand; and (7) is provided with a lever arm for easy access to certain nuts or bolt heads and employs a worm screw that is continuously turned in one direction during operation. The foregoing desired characteristics are provided by the unique power-driven wrench apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.